Hyperphosphatemia is a particular problem of patients with chronic renal insufficiency or chronic kidney disease (CKD). Approximately 70% of patients with end stage renal disease (ESRD) on renal dialysis therapy require treatment for hyperphosphatemia. This condition can lead to severe bone problems and metastatic calcification of skin and major organs and is associated with significant morbidity and mortality. Conventional dialysis fails to reduce the levels of phosphate in the blood, so that levels rise in time. Elevated phosphate levels are treated using a combination of dietary restrictions and phosphate-binding agents. Chronic renal insufficiency patients also suffer from secondary hyperparathyroidism.
Certain forms of lanthanum carbonate have been used to treat hyperphosphatemia in patients with renal failure (see, e.g., JP 1876384). U.S. Pat. No. 5,968,976, owned by the assignee of the present invention, describes the preparation and use in a pharmaceutical composition of certain hydrates of lanthanum carbonate for the treatment of hyperphosphatemia. U.S. Pat. Nos. 7,381,428 and 7,465,465, also both owned by the assignee of the present invention, disclose formulations containing lanthanum carbonate and lanthanum carbonate hydrate.
The non-calcium, non-resin phosphate binder lanthanum carbonate as a chewable tablet (FOSRENOL®, Shire Pharmaceuticals, Basingstoke, UK) is commonly used in clinical practice for the reduction of serum phosphorus in patients with CKD Stage 5 who are undergoing dialysis. For patients who have trouble chewing lanthanum carbonate tablets, who find chewable tablets unpalatable, or who find chewing tablets several times per day tiresome, there is a need in the art for alternative formulations containing lanthanum carbonate or lanthanum carbonate hydrate.